Comet Section        

 
 

COMET JOHNSON AT ITS BEST

2017-Jun-15

Saturn isn’t the only solar system body at its best this month. Comet Johnson is also at its best and is well placed as soon as it gets dark after sundown.

C/2015 V2 (Johnson) was first spotted by Jess Johnson of the Catalina Sky Survey back in November of 2015. It is a dynamically new comet with an original orbit almost indistinguishable from a parabola. Perturbations by the major planets have transformed its orbit to hyperbolic so this will be Johnson’s only trip through the inner solar system. Perihelion was only a few days ago (Jun 12) at a rather distant 1.64 au. Closest approach to Earth was earlier in the month (Jun 5) at 0.81 au.

Johnson is currently located over a dozen degrees south of Arcturus as it moves south through Virgo (finder charts can be found here and here). There has been some inconsistencies in its reported brightness. Binocular users are reporting it around magnitude 7.5 while telescope users are reporting it around magnitude 8.0 to 8.5. The plot below shows visual magnitudes submitted to the Comet Section. For the most part, those points above the green curve were made with binoculars while those below the curve were made with larger aperture telescopes. Regardless of what instruments you use, how bright do you think Johnson is?

The scatter in magnitudes may be due to Johnson’s bright broad dust tail. The tail is obvious in the below image taken by Chris Schur on June 15 with a 10″ Orion F/3.9 astrograph + SBIG ST10XME. It is possible that binocular observers are including some of the tail in their brightness estimate resulting in brighter magnitudes.

John D Sabia used a Canon DSLR and telephoto lens to image the comet on June 13. The image gives a good impression of what Johnson looks like in small apertures. The tail is also visible in this image.

So far the Comet Section has received 34 magnitude estimates from Salvador Aguirre, Carl Hergenrother, John Sabia and Willian Souza and 38 images from Charles Bell, Denis Buczynski, John Chumack, Carl Hergenrother, Manos Kardasis, Gianluca Masi, Richard Owens, Efrain Morales Rivera, John Sabia, Chris Schur and Michael Schwartz.

If you are out this weekend observing, please give Johnson a look. Whether you image it, make a magnitude estimate or just take a quick peek, submit your observations and impressions to the Comet Section.

 
 

ALPO COMET NEWS FOR JUNE 2017

2017-May-31

The nights may be getting shorter but they sure are warmer (and probably buggier as well). Two comets are nice and bright for June observers. C/2015 V2 (Johnson) is now 7th magnitude and visible for much of the night. Another long-period comet, C/2015 ER61 (PANSTARRS) is around 8th magnitude but only visible before dawn. For larger aperture observers, quickly fading 41P/Tuttle-Giacobini-Kresak and 10th magnitude 71P/Clark are also visible.

Last month the Comet Section received comet magnitude estimates for comets 41P/Tuttle-Giacobini-Kresak, C/2015 ER61 (PANSTARRS) and C/2015 V2 (Johnson) from Salvador Aguirre, Carl Hergenrother and Willian Souza. CCD images were received for comets 45P/Honda-Mrkos-Pajdusakova, C/2015 ER61 (PANSTARRS) and C/2015 V2 (Johnson) from Gianluca Masi, Richard Owens, John D. Sabia, Chris Schur and Michael Schwartz.

Evening C0mets

C/2015 V2 (Johnson) [Perihelion on 2017 June 12 at 1.64 au]

Comet Johnson will be at its best this month as it passes perihelion on June 12 at 1.64 au and closest approach to Earth on June 5 at 0.81 au. The comet is well placed and can be observed as soon as it gets dark in the evening. The comet starts the month a few degrees to the northeast of Arcturus and moves south during the month [Bootes (Jun 1-14) and Virgo (14-30)].  Currently between magnitude 7.5 and 8.0, the comet is an easy object for binocular and small telescope users. It should remain nearly as bright for most of the month through it may start to fade as it moves away from the Sun (1.64 to 1.66 au) and Earth (0.81 to 0.95 au).

C/Johnson was first seen back in November 2015 when it was 17th magnitude and located 6.5 au from the Sun. The fact that it was so bright when so far from the Sun suggests a large amount of dust was released in the years prior to discovery. This is rather typical of dynamically new comets making their first trip through the inner solar system. Dynamically new comets also usually brighten at a slow rate. While there was some hope it would brighten to 5th – 6th magnitude it looks like its current 7th magnitude is as bright as it willl get. All of that dust released over the past few years has provided Johnson with a nice bright dust tail. On June 1, the Earth is in line with Johnson’s orbit plane making the dust tail even more pronounced. The image below was taken by Chris Schur on May 28 and shows two tails pointing nearly 180 degrees apart (the broad bright dust tail to the lower left and a narrower fainter gas tail to the upper right).

71P/Clark [Perihelion on 2017 June 30 at 1.59 au]

Michael Clark discovered this comet photographically in 1973 from Mount John University Observatory in New Zealand. With an orbital period of 5.6 years, 2017 marks Clark’s 8th observed return. It spends the entire month in Scorpius (starting a few degrees to the southeast of Antares and moving slowly south from there). Its distance from the Sun is slowly decreasing as it approaches perihelion at 1.59 au on June 30. The comet will come as close to the Earth as it can on its present orbit on June 11 at 0.59 au. It is currently between magnitude 10.5 and 11.0 and should get a little brighter this month.

Morning Comets

41P/Tuttle-Giacobini-Kresak [Perihelion on 2017 Apr 12 at 1.05 au]

Now about 2 months removed from its close approach to Earth in April, 41P/T-G-K is currently between magnitude 9.5 and 10.0 and may fade to 13-14 by the end of the month. Unfortunately it did not experience one of its famous 10 magnitude outbursts. At least not yet. This month 41P will move through Hercules (Jun 1-4), Ophiuchus (4-13), Serpens Cauda (13-15), Ophiuchus (15-24) and Serpens Cauda (24-30) as it moves away from the Sun (1.24 to 1.47 au) and Earth (0.29 to 0.47 au). It is a morning object all month with an elongation that increases from 134 to 159 degrees. It starts the month between magnitude 9.5 and 10.0 and may fade to 13-14 by the end of the month.

C/2015 ER61 (PANSTARRS) [Perihelion on 2017 May 9 at 1.04 au]

June’s other long-period comet is C/2015 ER61 (PANSTARRS). It reached perihelion on May 9 at 1.04 au from the Sun and is moving away from the Sun (1.11 to 1.35 au) and Earth (1.38 to 1.56 au). Back in April, it experienced a 2 magnitude outburst. Since then the comet has settled back down and is currently 8th magnitude. Due to its increasing distance to the Sun and Earth it will slowly fade this month to 9th magnitude. All month, ER61 is a morning object moving through Pisces (Jun 1-15) and Aries (15-30).

Other Comets in the News

Newly discovered C/2017 K2 (PANSTARRS) is a bit of an enigma. Currently located 16 au from the Sun, K2 will not reach perihelion at 1.7 au until 2023! Extrapolating its current brightness results in a 5th magnitude comet for almost half of 2023. The main problem (actually there are a few) is that K2 is on a Halley-type with a 125 year period. If K2 were just as bright 125 or so years ago it would have been easily discovered. Perhaps the comet is experiencing an outburst. Only time, and monitoring, will tell.

As always, the Comet Section is happy to receive all comet observations, whether images, drawings or magnitude estimates.

- Carl Hergenrother (ALPO Comet Section Coordinator)

 
 

ALPO COMET NEWS FOR MAY 2017

2017-May-3

April was a busy month for the Comet Section as 4 comets were observed visually and 10 comets imaged with CCDs. The most exciting comet of the month was C/2017 E4 (Lovejoy). Discovered in March, this comet rapidly brightened to 6th magnitude before beginning a sudden fade. Gianluca Masi and Michael Schwartz observed it on 14 nights during April. Their latest observation shows a comet in distress and one whose nucleus may have already disintegrated. Most disintegrators are dynamically new so Lovejoy is a little strange in that it is a dynamically old comet. Still, there are a few examples of dynamically old comets that have disintegrated including C/1996 Q1 (Tabur) and even periodic comets 3P/Biela and 20D/Westphal.

Last month the Comet Section received comet magnitude estimates for comets 41P/Tuttle-Giacobini-Kresak, C/2015 ER61 (PANSTARRS), C/2015 V2 (Johnson) and C/2017 E4 (Lovejoy) from Salvador Aguirre, Carl Hergenrother and Willian Souza. In addition to C/2017 E4 (Lovejoy), CCD images were also received for comets 41P/Tuttle-Giacobini-Kresak, 45P/Honda-Mrkos-Pajdusakova, 71P/Clark, 73P/Schwassmann-Wachmann 3, 213P/Van Ness, 315P/LONEOS, C/2013 X1 (PANSTARRS), C/2015 ER61 (PANSTARRS) and C/2015 V2 (Johnson) from Charles Bell, John Chumack, Carl Hergenrother, Manos Kardasis, Gianluca Masi, Richard Owens, John D. Sabia, Chris Schur and Michael Schwartz.

This May morning observers will be able to follow a few comets in small telescopes as C/2015 ER61 (PANSTARRS) and C/2015 V2 (Johnson) are both 7th to 8th magnitude. Larger telescope users will be able to follow fading 41P/Tuttle-Giacobini-Kresak and brightening 71P/Clark.

Morning Comets

41P/Tuttle-Giacobini-Kresak [Perihelion on 2017 Apr 12 at 1.05 au]

41P/T-G-K approached to within 0.14 au of Earth on April 1 when it brightened to around magnitude 7.0. There was hope that the comet would experience an outburst like it did in 1973 but so far no luck. The comet is currently fading and is already a difficult object for many observers due to its low surface brightness coma. This month 41P will move through Hercules (May 1), Lyra (1-16) and Hercules (16-31) as it moves away from the Sun (1.08 to 1.23 au) and Earth (0.19 to 0.29 au). It is a morning object all month with an elongation that increases from 105 to 133 degrees. It starts the month between magnitude 7.5 and 8.0 and may fade to 9.0 to 10.0 by the end of the month.

Below is an image of 41P obtained by Chris Schur on April 29.

71P/Clark [Perihelion on 2017 June 30 at 1.59 au]

Michael Clark discovered this comet photographically in 1973 from Mount John University Observatory in New Zealand. With an orbital period of 5.6 years, 2017 marks this comet’s 8th observed return. Clark will start the month in Ophiuchus (May 1-22) at 11th magnitude before moving into Scorpius (23-31) and brightening to around 10th magnitude. Its distance from the Sun will shrink from 1.68 to 1.61 au. With a geocentric distance that drops from 0.74 to 0.60 au this month, the comet will come as close to the Earth as it can on its present orbit.

C/2015 ER61 (PANSTARRS) [Perihelion on 2017 May 9 at 1.04 au]

Comet PANSTARRS experienced a 2+ magnitude outburst in early April that brought it close to magnitude 6.0. Since then the comet has settled back down to its expected brightness of magnitude 7.5 to 8.0. It will reach perihelion on May 9 at 1.04 au from the Sun but be rather far from Earth at 1.20 to 1.37 au from Earth. A morning sky object, it will be in Pisces all month long as its elongation shrinks from 56 to 52 degrees. Barring further outbursts, PANSTARRS should remain around its current magnitude all May.

C/2015 V2 (Johnson) [Perihelion on 2017 June 12 at 1.64 au]

Comet Johnson is a little more than a month from its closest approach to Earth on June 5 at 0.81 au and perihelion on June 12 at 1.64 au. There has been some controversy on the comets-ml Yahoo group as to exactly how bright this comet. Observers using binoculars (such as myself) have reported the comet as bright at magnitude 7.6. Larger telescope observers are estimating the comet to be as faint as magnitude 9.0. While the comet is obvious to me in 10×50 binoculars, it is possible that my estimates are too bright due to contamination from a very bright dust tail that is unresolvable in small binoculars. Large aperture observers can differentiate the coma from the tail resulting in fainter total magnitude measurements. Regardless, Johnson should continue to brighten by another magnitude this month as it approaches the Sun (1.73 to 1.64 au) and Earth (1.01 to 0.82 au). It is still a morning object as its moves through Hercules (May 1-2) and Bootes (2-31).

As always, the Comet Section is happy to receive all comet observations, whether images, drawings or magnitude estimates.

- Carl Hergenrother (ALPO Comet Section Coordinator)

 
 

ALPO COMET NEWS FOR APR 2017

2017-April-5

The sky is now full of bright comets. We expected periodic comet 41P/Tuttle-Giacobini-Kresak to be around 6th magnitude this month, but two others have also reached that level of brightness. C/2015 ER61 (PANSTARRS) experienced a 2 magnitude outburst on April 4 or 5 and is now 6th magnitude. Newly discovered C/2017 E4 (Lovejoy) was only first seen on March 12 and has rapidly brightened to magnitude 6.5. Considering C/2015 V2 (Johnson) is also still brightening, though it is “only” at 9th magnitude, there’s lots to see this month.

Last month the Comet Section received comet magnitude estimates for comets 2P/Encke, 41P/Tuttle-Giacobini-Kresak, C/2015 ER61 (PANSTARRS), C/2015 V2 (Johnson) and C/2017 E4 (Lovejoy) from Salvador Aguirre, Carl Hergenrother, John D. Sabia and Willian Souza. CCD images were also received for comets 41P/Tuttle-Giacobini-Kresak, 45P/Honda-Mrkos-Pajdusakova, 71P/Clark, 73P/Schwassmann-Wachmann 3, 315P/LONEOS, C/2015 ER61 (PANSTARRS), C/2015 V2 (Johnson) and C/2017 E4 (Lovejoy) from John Chumack, Carl Hergenrother, Gianluca Masi, John D. Sabia, Chris Schur and Michael Schwartz.

Morning Comets

2P/Encke [Perihelion on 2017 March 10 at 0.34 au]

Comet Encke brightened to 8th magnitude in late February before passing too close to the Sun to be seen. Willian Souza of Brazil was able to reobserve Encke on March 26 at magnitude 7.7. Encke will only be visible from the southern hemisphere as it moves through Aquarius. It will fade from 9th to 12th magnitude as it recedes from both the Sun (0.65 to 1.16 au) and Earth (0.91 to 1.16 au).

41P/Tuttle-Giacobini-Kresak [Perihelion on 2017 Apr 12 at 1.05 au]

41P/T-G-K approached to within 0.14 au of Earth on April 1. Though this comet has brightened to 6th magnitude and is well place for northern observers, it has proved a difficult object to see. As is common for intrinsically faint comets that come close to Earth, 41P is a large object with a low surface brightness coma. As a result, low magnification and dark skies are needed to see it. CCD imagers are having a better time recording this comet.

The comet should slowly fade from 6th to 7th magnitude this month. Though perihelion occurs on April 12 and its heliocentric distance doesn’t change much, its geocentric distance increases from 0.14 to 0.19 au. The comet is currently circumpolar in Draco at a declination of +64 deg. The comet will still be a northern object at the end of the month in Hercules (declination of +39 deg). While 41P is prone to enormous outbursts it has been well behaved so far.

Image below was taken by John D. Sabia on March 30 showing structure in the inner coma of 41P.

C/2015 ER61 (PANSTARRS) [Perihelion on 2017 May 9 at 1.04 au]

Up to a few days ago C/2015 ER61 (PANSTARRS) was slowly brightening and shining at magnitude 8.5. After a two magnitude outburst, the comet is now around magnitude 6.2 to 6.5. C/PANSTARRS will reach perihelion on May 9 at 1.04 au from the Sun but never gets closer to Earth than 1.18 au. For northern observers, it will be located low in the morning sky. It will be better placed for southern observers. This month its distance from the Sun increases from 1.22 au to 1.05 au. Its geocentric distance stays around 1.23 to 1.18 au as it travels through Capricornus (Apr 1-5), Aquarius (5-12), Capricornus (12-18), Aquarius (18-29) and Pisces (29-30). How bright it will be this month is uncertain. If its recent outburst is a short-lived event, the comet may fade back to 8th magnitude. Alternately, additional outbursts may further its brightening.

C/2015 V2 (Johnson) [Perihelion on 2017 June 12 at 1.64 au]

Comet Johnson is inbound with a perihelion of 1.64 au and close approach to Earth at 0.81 au this summer. It is well placed for northern observers through perihelion. Its rate of brightening has been slow so this month it is only expected to brighten from magnitude 9.5 to 8.5. During April, it is a morning object in Hercules at an elongation that increases from 108 to 118 degrees. It starts the month 1.90 au from the Sun and 1.33 au from Earth. At the end of the month, these values decrease to 1.73 au from the Sun and 1.01 au from Earth. C/Johnson is still on pace to peak between magnitude 7.5 and 8.0 this summer.

Image below was taken on April 2 by Chris Schur.

C/2017 E4 (Lovejoy) [Perihelion on 2017 April 23 at 0.49 au]

The latest Comet Lovejoy was discovered by Australian amateur Terry Lovejoy with a CCD-equipped 14″ SCT f/1.9 Hyperstar system. The first magnitude estimates placed it near magnitude 12 but the comet rapidly brightened and is now around magnitude 6.5. As April starts, C/Lovejoy is located 0.72 au from the Sun and 0.61 au from Earth. At perihelion on April 23, it will be 0.49 and 1.10 au from the Sun and Earth. The comet could brighten by an additional magnitude or two by then. Lovejoy will become more difficult to observe as the month progresses as its elongation from the Sun shrinks from 45 deg to 20 deg. The comet will remain a morning object all month as it moves through Pegasus (Apr 1-12), Andromeda (12-27) and Triangulum (27-30).

Image below was taken on April 5 by Gianluca Masi and Michael Schwartz.

As always, the Comet Section is happy to receive all comet observations, whether images, drawings or magnitude estimates.

- Carl Hergenrother (ALPO Comet Section Coordinator)

 
 

ALPO COMET NEWS FOR Mar 2017

2017-March-1

This month visual observers will be able to follow four bright comets (five, if you include 2P/Encke though it may already be too close to the Sun for most observers as the month begins). Comet 45P/Honda-Mrkos-Pajdusakova is rapidly fading after passing 0.08 au from Earth last month. 41P/Tuttle-Giacobini-Kresak takes its turn passing close to the Earth (0.14 au) on April 1 and may reach 6th magnitude by the end of March. Two long-period comets should also become brighter than 10th magnitude [C/2015 ER61 (PANSTARRS) and C/2015 V2 (Johnson)].

Last month the Comet Section received comet magnitude estimates for comets 2P/Encke, 41P/Tuttle-Giacobini-Kresak and 45P/Honda-Mrkos-Pajdusakova from Salvador Aguirre and Carl Hergenrother. CCD images were also received for comets 2P/Encke, 41P/Tuttle-Giacobini-Kresak, 45P/Honda-Mrkos-Pajdusakova and C/2015 V2 (Johnson) from Richard Owens, Efrain Morales Rivera and John D. Sabia.

Evening Comets

2P/Encke [Perihelion on 2017 March 10 at 0.34 au]

If you live in the northern hemisphere and haven’t see Encke yet this apparition, the clock is ticking. On March 1, Encke will be a 7th-8th magnitude object located low in the western evening sky at an elongation of only 24 degrees. The comet rapidly drops closer to the Sun and will be invisible only a few days into March. A second opportunity to see Encke will occur between March 9 and 14 via our computers as the comet will be within the field-of-view of the LASCO C3 instrument on the SOHO spacecraft. Observers south of the equator will be able to observe Encke towards the end of the month as it reappears in the morning sky at 8th magnitude. The comet starts the month at a heliocentric distance of 0.41 au. Perihelion occurs on March 10 at 0.34 au. By the end of the month it will be at 0.64 au from the Sun. Its distance from Earth drops from 0.81 au on the 1st to 0.66 au on the 12th before increasing to 0.91 au at the end of the month. Encke will be traveling through Pisces (Mar 1-10) and Aquarius (11-31).

45P/Honda-Mrkos-Pajdusakova [Perihelion on 2016 December 31 at 0.53 au]

Comet 45P/Honda-Mrkos-Pajdusakova is rapidly fading after its close approach to Earth (0.08 au) on Feb 11. Though it was a small condensed object with a long gas tail prior to perihelion, it became a large, low surface brightness object post-perihelion. As is often the case with such objects, observing conditions and the equipment used can greatly affect the view. The comet can easily be missed if the sky was too bright or too high of a magnification was used. As a result, the comet was considered a disappointment by some. Salvador Aguirre and Carl Hergenrother were able to observe the comet in 7×50 and 10×50 binoculars at around magnitude 6.5 a few days prior to close approach. In my 10×50s the coma was over a half degree in diameter. Unfortunately the date of close approach and the days after were compromised by a nearly Full Moon. By the time the Moon was out of the sky, 45P had faded to magnitude 7.6. This month the comet starts at 9th magnitude but continues fading to 13th by the end of March as it moves through Leo (Mar 1-2, 6-9, 13-31) and Leo Minor (2-6, 8-13). Its distances from the Sun and Earth increase from 1.23 to 1.64 au and from 0.25 to 0.74 au, respectively.

41P/Tuttle-Giacobini-Kresak [Perihelion on 2017 Apr 12 at 1.05 au]

Comet 41P/Tuttle-Giacobini-Kresak will also make an impressive close approach to Earth. Though it won’t come as close as 45P did back in February, 41P is an intrinsically brighter comet and will appear brighter in apparent magnitude. Still, 41P may be more difficult to see than its brightness suggests to those observing under less than dark skies. The comet starts the month around magnitude 9.6 and will brighten  to magnitude 8.3 on 3/11, 7.2 on 3/21, and 6.5 on 3/31. Closest approach occurs on April 1 at 0.14 au. This is nearly the closest this comet can come to Earth on its current orbit and it won’t pass this close again till 2066.

T-G-K is outburst prone and experienced two 10-magnitude outbursts in 1973. Smaller outbursts also occurred in 1995 and 2001. If T-G-K were to experience an outburst during this return it could become a naked eye object. During March, T-G-K moves from 1.19 to 1.06 au from the Sun and 0.22 to 0.14 au from Earth. It will be located in Leo (Mar 1-5), Leo Minor (5-12), Ursa Major (12-29), Draco (29-31) as its elongation drops from 155 to 110 degrees in the evening sky.

Morning Comets

C/2015 V2 (Johnson) [Perihelion on 2017 June 12 at 1.64 au]

Comet Johnson is inbound with a perihelion of 1.64 au and close approach to Earth at 0.81 au this summer. It is well placed for northern observers through perihelion. Its rate of brightening has been slow so this month it is only expected to brighten from magnitude 10.4 to 9.6. During March, it is a morning object in Hercules (Mar 1-31) at an elongation that increases from 101 to 108 degrees. It starts the month 2.13 au from the Sun and 1.70 au from Earth. At the end of the month, these values decrease to 1.90 au from the Sun and 1.34 au from Earth.

C/2015 ER61 (PANSTARRS) [Perihelion on 2017 May 9 at 1.04 au]

C/2015 ER61 (PANSTARRS) will reach perihelion on May 9 at 1.04 au from the Sun but never gets closer to Earth than 1.18 au. As a result, ER61 may only brighten to 8th magnitude at is brightest in May. For northern observers, it will be located low in the morning sky. It will be better placed for southern observers. This month its distance from the Sun increases from 1.54 au to 1.23 au. Its geocentric distance grows from 1.58 to 1.23 au as it travels through Sagittarius (Mar 1-27) and Capricornus (27-31). It is currently 10-11th magnitude and may brighten to 9th magnitude by the end of the month though its rate of brightening also appears to be rather slow.

73P/Schwassmann-Wachmann 3 [Perihelion on 2017 March 16 at 0.97 au]

A newly discovered component of the split comet 73P/Schwassmann-Wachmann 3 was observed in outburst during February. Component 73P-BT is currently 11-12th magnitude and located within arc minutes of the primary component 73P-C (a little fainter at 13th magnitude). CCD imagers and large aperture visual observers are asked to monitor this comet for additional outbursts or splitting events. The comet is located low in the eastern morning sky and will only get lower as the month progresses. 73P has a long history of splitting events following an initial split in 1995. Though hundreds to thousands of components were observed during its close flyby of Earth in 2006, components C and BT are the only two known to be currently active.

As always, the Comet Section is happy to receive all comet observations, whether images, drawings or magnitude estimates.

- Carl Hergenrother (ALPO Comet Section Coordinator)

 
 

ALPO COMET NEWS FOR FEB 2017

2017-February-11

Sorry for the late update. The big story this month is the extreme close approach of comet 45P/Honda-Mrkos-Pajdusakova to Earth on February 11 at 0.08 au. A few other comets, including frequent visitor 2P/Encke, will be visible in small telescopes.

Evening Comets

2P/Encke [Perihelion on 2017 March 10 at 0.34 au]

Comet Encke is making its 63rd observed apparition since it was first seen in 1786. Encke will become a visual object this February as it brightens from 10th to 7th magnitude in Pisces. Its elongation drops from 46 to 24 degrees. as its distance from the Sun decreases from 0.91 to 0.42 au and geocentric distance decreases from 1.27 to 0.81 au.

41P/Tuttle-Giacobini-Kresak [Perihelion on 2017 Apr 12 at 1.05 au]

This comet was discovered on three separate occasions: in 1858 by Horace Tuttle, 1907 by Michel Giacobini and 1951 by Lubor Kresak. 2017 marks 41P’s 11th observed apparition. Nominally 41P should become 6th magnitude by late March. I say nominally because this comet is prone to outbursts. In 1973, T-G-K experienced two 10-magnitude outbursts. Smaller outbursts also occurred in 1995 and 2001. If T-G-K were to experience an outburst during this return it could become a naked eye object. Perihelion is on April 13 at 1.05 au and close approach to Earth is on March 27 at 0.14 au. During February, T-G-K will brighten from 13th to 9th magnitude as it moves from 1.40 to 1.19 au from the Sun and 0.42 to 0.22 au from Earth. It will be located in Leo near opposition all month.

Morning Comets

45P/Honda-Mrkos-Pajdusakova [Perihelion on 2016 December 31 at 0.53 au]

Comet 45P/H-M-P brightened up to 6th magnitude before it was lost in the glow of dusk in early January. At that time is was highly condensed and displayed a hint of bluish-green in my 30×125 binoculars. The comet is currently racing higher into the eastern sky at dawn. Salvador Aguirre spotted it on Feb 10 at magnitude 6.5. A night earlier, I spotted it in 10×50s as a large diffuse glow over 1/2 degree across. Its appearance was very similar to that of 252P/LINEAR which made a close approach last year. Unfortunately, the best for this comet is probably over as large, diffuse, low surface brightness objects usually don’t fare well against a bright Moon. The comet will still be visible to small telescope and binocular observers throughout the month but will be fading (probably no brighter than 9th magnitude by the end of the month). This month, its heliocentric distance increases from 0.83 to 1.23 au while its geocentric distance initially decreases from 0.16 au to February 11’s close approach at 0.08 au and back to 0.25 au as it moves through Aquila (Feb 1-7), Hercules (7-11), Corona Borealis (11-13), Bootes (13-15), Canes Venatici (15-20), Coma Berenices (20-21), Ursa Major (21-25) and Leo (25-28). Elongation climbs from a still too low 17 degrees on the 1st to 45 deg on the 7th, 90 deg on the 12th, and a close to opposition 159 deg at the end of the month.

C/2015 ER61 (PANSTARRS) [Perihelion on 2017 May 9 at 1.04 au]

C/2015 ER61 (PANSTARRS) will reach perihelion on May 9 at 1.04 au from the Sun but never gets closer to Earth than 1.18 au. As a result, ER61 may only brighten to 8th magnitude at is brightest in May. For northern observers, it will be located low in the morning sky. It will be better placed for southern observers. This month its distance from the Sun increases from 1.86 au to 1.54 au. Its geocentric distance grows from 2.08 to 1.58 au as it travels through Ophiuchus (Feb 1-23) and Sagittarius (23-28). It is currently 10-11th magnitude and may brighten to 9th magnitude by the end of the month.

C/2015 V2 (Johnson) [Perihelion on 2017 June 12 at 1.64 au]

Comet Johnson is inbound with a perihelion of 1.64 au and close approach to Earth at 0.81 au this summer. It is well placed for northern observers through perihelion. Now is a good time for CCD imagers and large aperture visual observers to watch C/Johnson brighten from its current 10th magnitude to a peak of 6-7th magnitude. This month, it is a morning object in Bootes (Feb 1-9) and Hercules (9-28) at an elongation that increases from 96 to 101 degrees. It starts the month 2.36 au from the Sun and 2.05 au from Earth. At the end of the month, these values decrease to 2.13 au from the Sun and 1.70 au from Earth.

As always, the Comet Section is happy to receive all comet observations, whether images, drawings or magnitude estimates.

- Carl Hergenrother (ALPO Comet Section Coordinator)

 
 

ALPO COMET NEWS FOR JAN 2017

2017-January-1

Happy New Year! 2017 promises to be a busy year for comet observers as no less than 7 comets are predicted to become brighter than 10th magnitude: 2P/Encke, 41P/Tuttle-Giacobini-Kresak, 45P/Honda-Mrkos-Pajdusakova, 96P/Machholz, C/2015 ER61 (PANSTARRS), C/2015 V2 (Johnson), C/2016 U1 (NEOWISE). Of course there are the comets yet to be discovered as well as the dozens of fainter comets within reach of CCDs.

The last month of 2016 was a productive one for the ALPO Comet Section. CCD imagers continued to monitor a number of comets, both bright and faint, while visual observations were reported for the month’s two brightest comets. While January will see a slow down in visual observations as we lose our two bright comets to the glare of the Sun, the action will pick up again in February.

During December, CCD observers Denis Buczynski, Carl Hergenrother, Efrain Rivera Morales, Richard Owens and John D. Sabia contributed images of the following comets: 2P/Encke, 41P/Tuttle-Giacobini-Kresak, 43P/Wolf-Harrington, 45P/Honda-Mrkos-Pajdusakova, 56P/Slaughter-Burnham, 74P/Smirnova-Cherynkh, 93P/Lovas, 174P/Echeclus, 226P/Pigott-LINEAR-Kowalski, 315P/LONEOS, C/2010 U3 (Boattini), C/2013 US10 (Catalina), C/2015 VL62 (Lemmon-Yeung-PANSTARRS), C/2015 V2 (Johnson), C/2015 X7 (ATLAS), C/2016 N4 (MASTER), and C/2016 T2 (Matheny). Visual comet magnitude estimates were submitted by Carl Hergenrother, John D. Sabia and Willian Souza for 45P/Honda-Mrkos-Pajdusakova and C/2016 U1 (NEOWISE).

The effort to digitize the archives of the Comet Section and place them online continues. Currently the Section Gallery contains over 2300 images and drawings of 215 different comets.

Evening Comets

45P/Honda-Mrkos-Pajdusakova [Perihelion on 2016 December 31 at 0.53 au]

Comet 45P/H-M-P has been brightening as predicted with visual observers placing it at magnitude 7.2-7.3 at the end of December. After passing perihelion on New Year’s Eve, its orbit will carry 45P between the Sun and Earth. As a result, we will lose sight of the comet during the first week of January. Not to worry, the best is yet to come as 45P will become an easily observable object (up to 6th-7th magnitude) in the morning sky starting in early February as it passes within 0.08 au of Earth. This month, its heliocentric distance increases from 0.53 to 0.84 au while its geocentric distance crashes from 0.68 to 0.16 au as it moves through Capricornus (Jan 1-15) and Aquarius (15-31) in the evening sky.

The image below was taken by Richard Owens on December 27.

2P/Encke [Perihelion on 2017 March 10 at 0.34 au]

Comet Encke is back again and making its 63rd observed apparition since it was first seen in 1786. Encke will become a visual object this February as it brightens to 7th magnitude. This month, the comet rapidly brightens from ~13th to 10th magnitude. The Section asks that CCD imagers monitor Encke as it approaches perihelion. Note, that Encke’s appearance depends on what filter is used. The comet may still appear asteroidal in the red while a large gas coma is already detectable in the blue. This month Encke is an evening object moving through Pisces as its elongation drops from 97 to 68 degrees. Its distance from the Sun decreases from 1.39 to 0.91 au while its geocentric distance decreases from 1.42 to 1.26 au.

Morning Comets

C/2015 V2 (Johnson) [Perihelion on 2017 June 12 at 1.64 au]

Jess Johnson of the Catalina Sky Survey discovered this long period comet on November 3, 2015 with the 0.68-m Catalina Schmidt. The comet is inbound with a perihelion of 1.64 au and close approach to Earth at 0.81 au this summer. It is well placed for northern observers through perihelion. Now is a good time for CCD imagers and large aperture visual observers to watch C/Johnson brighten from its current 12th magnitude to a peak of 6-7th magnitude. This month, it is a morning object in Bootes at an elongation that increases from 89 to 96 degrees. It starts the month 2.64 au from the Sun and 2.47 au from Earth. At the end of the month, these values decrease to 2.36 au from the Sun and 2.05 au from Earth.

C/2016 U1 (NEOWISE) [Perihelion on 2017 January 14 at 0.32 au]

Comet NEOWISE is a surprise comet. Only 19th magnitude when discovered in late October, the comet rapidly brightened and was approaching magnitude 8.0 at the end of December. The comet will be lost to most observers during the first week of the month as it moves too close to the Sun. At that time it may be as bright as 7th magnitude. Southern hemisphere observers may be able to pick the comet up again in February though it may already be too faint for visual observation. Northern observers won’t get another shot at NEOWISE till August when it may be too faint even for CCD imagers. This month its distance from the Sun drops from 0.49 au to a perihelion on January 14 of 0.32 au. The distance grows to 0.61 au at the end of the month. Its geocentric distance grows from 0.89 to 1.48 au. Though mostly unseen, C/NEOWISE will travel through Ophiuchus (Jan 1-7), Serpens (7-10), Scutum (10-11), Sagittarius (11-26) and Microscopium (26-31).

New Discoveries

Only one comet discovery was reported in the past month. Yet another interesting asteroid on a very cometary orbit was announced.

C/2016 X1 (Lemmon) is a long-period comet with a large perihelion distance of 7.6 au. It was found by G. J. Leonard with the Mount Lemmon 1.5-m reflector. Even though perihelion will not occur till May of 2019, the comet shouldn’t get much brighter than its current 20th magnitude.

Last month we reported on 2016 VY17, an apparently asteroidal object on a Halley-type orbit. A similar object has been recently announced. 2016 VZ18 is on a long-period comet orbit with a period of ~2700 years. Perihelion will occur in early March at 0.91 au. in early April it will approach to within 0.53 au of Earth. If it remains inactive, VZ18 will not get any brighter than magnitude 20. If it does ‘turn on’, it could become much brighter. CCD observers are encouraged to monitor this object and send your images and photometry to the Comet Section. Who knows, maybe you will be the first to notice VZ18 as an active comet.

As always, the Comet Section is happy to receive all comet observations, whether images, drawings or magnitude estimates.

- Carl Hergenrother (ALPO Comet Section Coordinator)

 
 

ALPO COMET NEWS FOR DECEMBER 2016

2016-December-2

With 2016 drawing to a close, it is a good time to look back on the comet year that was. The brightest comets of 2016 were 252P/LINEAR (mag 4), C/2013 US10 (Catalina) (mag 6), C/2013 X1 (PANSTARRS) (mag 6), and C/2014 S2 (PANSTARRS) (mag 8). Before the year ends, two more comets may work their way onto the list. Though comet 45P/Honda-Mrkos-Pajdusakova will be a much easier target to observe in February, observers with a good southwestern horizon may peak a glimpse of it rapidly brightening this month. C/2016 U1 (NEOWISE) is surrounded by some uncertainty, but recent observations suggest this comet will become bright enough for visual observers this month as well.

During November, CCD observers Denis Buczynski and Gianluca Masi contributed images of 56P/Slaughter-Burnham, 74P/Smirnova-Cherynkh, 117P/Helin-Roman-Alu, 128P/Shoemaker-Holt, 226P/Pigott-LINEAR-Kowalski, C/2010 U3 (Boattini), C/2013 US10 (Catalina), C/2013 V4 (Catalina), P/2015 TP200 (LINEAR), C/2015 V1 (PANSTARRS), C/2015 V2 (Johnson), C/2015 VL62 (Lemmon-Yeung-PANSTARRS), and C/2016 T3 (PANSTARRS). Also, visual observer Per-Jonny Bremseth has been contributing his extensive collection of excellent comet drawings going back to C/1969 Y1 (Bennett).

Evening Comets

45P/Honda-Mrkos-Pajdusakova [Perihelion on 2016 December 31 at 0.53 AU]

Comet 45P/Honda-Mrkos-Pajdusakova… Honestly, that is the kind of name a comet should have. When 45P was discovered back in 1948, comets were routinely named after three discoverers. That practice has fallen out of favor. In fact, no new discoveries in 2016 even share two names. The two tri-named comets mentioned above (Lemmon-Yeung-PANSTARRS and Pigott-LINEAR-Kowalski) represent the only comets named after three discoverers since 2003.

Comet 45P/Honda-Mrkos-Pajdusakova is out best bet to break our recent bright comet drought. 2016 will be the 12th observed apparition for 45P as it rounds the Sun once every ~5.3 years. It is one of a class of Jupiter-family comets that have small perihelion distances but are only active (and bright) when close to the Sun. As December begins, the comet is around 11th to 12th magnitude. It will be around 9th magnitude by the middle of the month and 7th magnitude by the end. Observing this comet will still be difficult as it is usually very diffuse (as is typical for a gaseous comet) and located low in the southwestern sky during the evening as it traverses Sagittarius (Dec 1-14) and Capricornus (14-31). For observers at 40N, the comet will only be located at an elevation of ~10 degrees at the end of astronomical twilight all month long. After solar conjunction in early February, 45P will rapidly climb into the morning sky as a 7th-8th magnitude object as it passes within 0.08 AU of Earth. This month, its heliocentric and geocentric distances decrease from 0.81 to 0.53 AU and 1.27 to 0.68 AU, respectively.

2P/Encke [Perihelion on 2017 March 10 at 0.34 AU]

Comet Encke is back again and making its 63rd observed apparition since it was first seen in 1786. Encke will be a visual object this February as it brightens to 7th magnitude. This month, the comet is only of interest to CCD imagers as it rapidly brightens from ~17th to 14th magnitude. The Section asks that CCD imagers start following Encke now so we can watch it brighten and develop as it travels towards perihelion. An interesting imaging activity is to monitor the development of its coma in different colors. In the past, the gas coma has developed faster than the dust coma so Encke appeared to have a large coma in a blue filter while still appearing inactive in a red filter. This month Encke is an evening object moving through Pisces at an elongation that drops from 97 to 68 degrees. It distance from the Sun decreases from 1.79 to 1.39 AU while its geocentric distance increases slightly from 1.37 to 1.42 AU.

Morning Comets

C/2015 V2 (Johnson) [Perihelion on 2017 June 12 at 1.64 AU]

Jess Johnson of the Catalina Sky Survey discovered this long period comet on November 3, 2015 with the 0.68-m Catalina Schmidt. The comet is inbound with a perihelion of 1.64 AU and close approach to Earth at 0.81 AU this summer. It is well placed for northern observers through perihelion. Now is a good time for CCD imagers and large aperture visual observers to watch C/Johnson brighten from its current 12th magnitude to a peak of 6-7th magnitude. This month, it is a morning object in Canes Venatici (Dec 1-19) and Bootes (19-31) at an elongation that increases from 79 to 89 degrees. It starts the month 2.93 AU from the Sun and 2.96 AU from Earth. At the end of the month, these values decrease to 2.64 AU from the Sun and 2.47 AU from Earth.

C/2016 U1 (NEOWISE) [Perihelion on 2017 January 14 at 0.32 AU]

The discovery of this comet was announced in the previous ALPO Comet News. Initially reported as very faint by most CCD astrometrists, recent CCD and visual observations show it to be much brighter than originally thought. At the end of November, C/NEOWISE is around 11-12th magnitude. With perihelion on January 14 at a very small distance of 0.32 AU, the comet may brighten to 7-8th magnitude before getting too close to the Sun in early January. This month, C/NEOWISE travels through Canes Venatici (Dec 1-3), Bootes (3-12), Corona Borealis (12-16), Serpens (16-17), Hercules (17-24), and Ophiuchus (24-31) in the morning sky as its heliocentric distance drops from 1.13 to 0.49 AU and its geocentric distance from 0.77 to a minimum of 0.71 on Dec 12/13 before growing to 0.71 AU at the end of the month.

New Discoveries

Amazingly since the last Comet Section News posting, no comet discoveries have been officially reported. That said, an asteroid on a very cometary orbit was announced.

2016 VY17 is on Halley-type orbit with a retrograde inclination of 148 deg and period of 37.5 years. Perihelion will occur in early July at 1.66 au and closest approach to Earth follows in mid-August at 0.89 au. If the object is truly inactive it will brighten to 17th magnitude in mid-August. It is very possible that VY17 will become active and if so, it could become bright enough for visual observation. CCD observers are encouraged to monitor this object and send your images and photometry to the Comet Section. Who knows, maybe you will be the first to notice VY17 as an active comet.

As always, the Comet Section is happy to receive all comet observations, whether images, drawings or magnitude estimates.

- Carl Hergenrother (ALPO Comet Section Coordinator)

 
 

ALPO COMET NEWS FOR NOVEMBER 2016

2016-November-7

We are still in the midst of a bright comet drought this month. While there have been no visual magnitude estimates submitted to the ALPO Comet Section since July, CCD observers have been busy imaging some of the fainter comets. During October, Richard Owens and Gianluca Masi contributed images of 2P/Encke, 53P/Van Biesbroeck, 93P/Lovas, 174P/Echeclus, C/2014 A4 (SONEAR), C/2016 A8 (LINEAR), and C/2016 M1 (PANSTARRS). Though no comets are expected to be brighter than magnitude 11-12 in November, there are some comets that will become bright during the coming months that would benefit from CCD imaging now as they brighten.

Evening Comets

45P/Honda-Mrkos-Pajdušáková [Perihelion on 2016 December 31 at 0.53 AU]

2016 will be the 12th observed apparition for Comet Honda-Mrkos-Pajdušáková as it rounds the Sun once every ~5.3 years. As November begins, there have been no reported observations of this comet. Historically, 45P brightens rapidly when close to the Sun and should be ~17th magnitude. The lack of observations may be its location very low in the evening sky as it traverses Sagittarius. CCD users imaging Venus and Mars can try to go a bit deeper for 45P as it should brighten to 12th magnitude by the end of the month. Visual observers will be able to observe 45P very low in the evening sky starting in December through early January as it brightens to 7th magnitude. After solar conjunction in early February, 45P will rapidly climb into the morning sky as a 7th-8th magnitude object as it passes within 0.08 AU of Earth. This month, its heliocentric and geocentric distances decrease from 1.23 to 0.81 AU and 1.57 to 1.27 AU, respectively.

2P/Encke [Perihelion on 2017 March 10 at 0.34 AU]

Comet Encke is back again. In fact, it never really ‘leaves’ in that it is visible even at aphelion if one can image down to ~20th magnitude. 2017 will mark Encke’s 63rd observed apparition since it was first seen in 1786. The high number of returns is due not only to Encke’s long observational history but also due to it having the shortest known cometary orbital period at 3.3 years. Encke will be a visual object this February as it brightens to 7th magnitude. This month, the comet is only of interest to CCD imagers as it will be ~17th magnitude. The Section asks that CCD imagers start following Encke now so we can watch it brighten and develop as it heads towards perihelion. An interesting imaging activity is to monitor the development of its coma in different colors. In the past, the gas coma has developed faster than the dust coma so Encke appeared to have a large coma in a blue filter while still appearing inactive in a red filter. This month Encke is an evening object moving through Pegasus (Nov 1-7) and Pisces (7-30) at an elongation that drops from 134 to 97 degrees. It distance from the Sun decreases from 2.12 to 1.79 AU while its geocentric distance increases slightly from 1.30 to 1.37 AU.

Morning Comets

C/2015 V2 (Johnson) [Perihelion on 2017 June 12 at 1.64 AU]

Jess Johnson of the Catalina Sky Survey discovered this long period comet on November 3, 2015 with the 0.68-m Catalina Schmidt. The comet is inbound to a perihelion of 1.64 AU and close approach to Earth of 0.81 AU this summer. It is well placed for northern observers through perihelion. As a result, now is a good time for CCD imagers and large aperture visual observers to watch C/Johnson brighten from its current 13th magnitude to a peak of 6-7th magnitude. This month, it is a morning object in Canes Venatici at an elongation that increases from 67 to 79 degrees. It starts the month 3.21 AU from the Sun and 3.47 AU from Earth. At the end of the month, these values decrease to 2.93 AU from the Sun and 2.96 AU from Earth.

C/2016 U1 (NEOWISE) [Perihelion on 2017 January 14 at 0.32 AU]

This will be an interesting comet to watch over the coming few months. With perihelion on January 14 at a very small distance of 0.32 AU, there are hopes that this comet could become bright. Dampening those hopes is the fact that the comet is currently 1.6 AU from the Sun and still only 20th magnitude. This suggests that C/NEOWISE is intrinsically very faint. While it may brighten significantly as it approaches perihelion, it may not become bright enough for visual observation. While currently out of range for most CCD imagers, I’ll send out a mid-month Comet Section news update if the comet does brighten enough to warrant additional attention. This month, C/NEOWISE travels through Ursa Major into Canes Venatici in the morning sky as its heliocentric distance drops from 1.67 to 1.13 AU and its geocentric distance from 1.32 to 0.77 AU.

New Discoveries

Since the last Comet Section News posting, a number of new comets were discovered in addition to the already mentioned C/2016 U1 (NEOWISE).

C/2016 T3 (PANSTARRS) is one of three dynamically old long period comets (meaning this is not their first trip through the inner Solar System) discovered since the last Comet Section news update. C/2016 T3 was found by the Pan-STARRS program at 20th magnitude. With perihelion occurring on September 8, 2017 at 2.67 AU from the Sun, it may brighten by a few magnitudes to ~17.

C/2016 T2 (Matheny) is also a dynamically old long period comet with a perihelion distance of 1.92 AU and inclination of 81 degrees. It was 18th magnitude when Rose Matheny of the Catalina Sky Survey used the 1.5-m Mount Lemmon reflector first saw it on October 10. Perihelion occurs this December 27 when the comet will peak at 17-18th magnitude.

C/2016 T1 (Matheny) was also found by Rose Matheny with the Catalina Sky Survey 1.5-m Mount Lemmon reflector. This comet was found 4 days before C/2016 T2. The two comets are Matheny’s only comet discoveries. Similar to C/2016 T2, C/2016 T1 is a dynamically old long period comet but with a perihelion distance of 2.30 AU, perihelion date of February 2, 2017, and inclination of 129 degrees. It was 18th magnitude at discovery and may brighten another magnitude.

P/2016 S1 (PANSTARRS) is a short period comet first seen by Pan-STARRS on September 21. It is on a 24 year period orbit with a 94 degree inclination and a March 16, 2017 perihelion at 2.41 AU from the Sun. The comet may brighten to 17th magnitude from its discovery brightness of 19th magnitude.

P/2016 SV (PANSTARRS) is another short period comet with a 6.9 year period. It reaches perihelion on September 11, 2016 at 2.22 AU from the Sun. It was 19th magnitude when discovered by Pan-STARRS on September 19. Pre-discovery observations by Pan-STARRS from June 20 and the Catalina Sky Survey from 2009 were identified after discovery. It is unlikely this comet will get much brighter than 19th magnitude.

P/2016 R4 (Gibbs) was found by Alex Gibbs of the Catalina Sky Survey with the Mount Lemmon 1.5-m reflector. P/2016 R4 was first seen on September 10 at 18th magnitude. It has a 12.3 year period and passed perihelion on July 16, 2016 at q = 2.80 AU.

As always, the Comet Section is happy to receive all comet observations, whether images, drawings or magnitude estimates.

- Carl Hergenrother (ALPO Comet Section Coordinator)

 
 

ALPO COMET NEWS FOR SEPTEMBER/OCTOBER 2016

2016-September-17

We are in the midst of a bright comet drought. August and the first half of September saw no comets brighter than ~10th magnitude and it looks like the rest of September and October will see the same unless there is a new bright discovery or outburst. Currently the next comet predicted to brighten above 10th magnitude will be short-period 45P/Honda-Mrkos-Pajdušáková in late December.

Just a bit fainter than 10th magnitude are a number of comets that are viable targets for large aperture visual observers and CCD imagers. Images of a few fainter comets have been submitted to the Comet Section, including 29P/Schwassmann-Wachmann, 53P/Van Biesbroeck, C/2016 A8 (LINEAR) by Charles Bell, Manos Kardasis and John Sabia. The table below is from the main Comet Section webpage and lists comets 12th magnitude or brighter.

New Discoveries

Since the last Comet Section News posting, a number of comets have been discovered. Most are faint though the most recent find comes with an interesting story.

C/2016 R3 (Borisov) – Gennady Borisov found this comet on September 11 with a 0.3-m f/1.5 Genon astrograph + CCD at the MARGO Observatory in the Crimea. It is his 6th comet discovery since 2013. While Gennady and other CCD observers reported the comet at 16th magnitude, experienced observer Alan Hale was able to observe it visually at 13th magnitude. Perihelion will occur on October 10 at 0.45 AU. Unfortunately, C/2016 R3’s elongation is ~30° and dropping fast in the morning sky. It is possible this comet will only be observable for another week since it will be too close to the Sun to be observed when bright.

Interestingly, the orbit of C/2016 R3 (Borisov) is very similar to that of C/1915 R1 (Mellish). The 1915 comet was discovered by John E. Mellish, purported early observer of craters on Mars and namesake of the Martian crater Mellish. It was one of five comets discovered by Mellish and his second of 1915. With perihelion in 1915 being on October 13, it had almost the exact same, and poor, observing circumstances as in 2016. So far orbit computers have not been able to positively link the 1915 and 2016 observations for orbit periods of ~100, 50, 25 and 20 years. There is no doubt that the 1915 and 2016 comets are related though they may be separate components of a splitting event. The faintness of the 2016 comet relative to the 1915 comet also suggests that the two may be different.

C/2016 R2 (PANSTARRS) – The Pan-STARRS survey found this 19th magnitude comet with their 1.8-m Pan-STARRS1 telescope in Hawaii on September 7. It is a long-period comet with an inclination of 58° and perihelion at 2.64 AU from the Sun in May of 2018. It could brighten to 13th magnitude in 2018.

C/2016 Q4 (Kowalski) – Richard Kowalski discovered this 18th magnitude comet on August 30 with the Mount Lemmon 1.5-m. It is a Centaur-type comet with an inclination of 7°, period of 69 years and perihelion in January of 2018 at 7.1 AU from the Sun. It could brighten by another magnitude between now and perihelion.

C/2016 Q2 (PANSTARRS) – Discovered on 2016 August 26 at 21st magnitude by Pan-STARRS. It is a long-period comet with an inclination of 63° and perihelion is not till 2020 January 3 at 3.43 AU from the Sun. It could brighten to 12-13th magnitude in 2019/2020.

C/2016 P4 (PANSTARRS) – Discovered on August 7 at 22nd magnitude by Pan-STARRS. It is a long-period comet with an inclination of 30° and perihelion on October 16 at 5.89 AU from the Sun. Magnitude 22 is as bright as this comet will get.

P/2016 P2 (PANSTARRS) – Discovered on August 8 at 21st magnitude by Pan-STARRS. It is a short-period comet with a period of 9.3 years. Perihelion was back in November of 2015 at 3.12 AU. This comet will not get any brighter.

P/2016 P1 (PANSTARRS) – Discovered on August 1 at 22nd magnitude by Pan-STARRS. It is a short-period comet with a period of 5.8 years. Perihelion was back in September of 2015 at 2.28 AU. This comet will also not get any brighter.

C/2016 N6 (PANSTARRS) – Discovered on July 14 at 20th magnitude by Pan-STARRS. It is a long-period comet with an inclination of 106° and perihelion on 2018 July 18 at 2.67 AU from the Sun. It may reach 14th magnitude during 2018.

Also the following periodic comets were recovered and numbered.

343P/NEAT-LONEOS = P/2016 P3 = P/2003 SQ205 [T = 2017 Jan 27, q = 2.28 AU, P = 12.8 yrs, expected peak mag = 17]

342P/SOHO = P/2016 N5 = P/2011 E1 = P/2005 W4 = P/2000 O3 – [T = 2016 Jul 1, q = 0.05 AU, P = 5.3 yrs, expected peak mag = very faint outside of SOHO FOV]

As always, the Comet Section is happy to receive all comet observations, whether images, drawings or magnitude estimates.

- Carl Hergenrother (ALPO Comet Section Coordinator)

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